Updated ASHRAE Climate Zone Maps

Z Smith

Principal | Director of Sustainability & Building Performance

Eskew+Dumez+Ripple

LEEDuser Premium Member

4 thumbs up

April 7, 2023

We all know the climates are shifting, and the ASHRAE standard that gets invoked for energy codes is shifting along with them--though not in perfect sync. Louisiana is leaping from ASHRAE 90.1-2007 energy code to 2021 IECC (boom!). The 2021 IECC as published uses relatively old climate maps; for Louisiana, at least, the same as the 90.1-2007. However, in late 2021, ASHRAE approved 'Addendum a' to ASHRAE 169-2020 Climatic Data for Building Design Standards. In the old maps, the southern half of our state was in Climate Zone 2 while the northern half was in CZ 3. In the new maps, all but 4 parishes (counties, to you) of the state are shown in CZ2. Our State Energy Code Commission voted to declare the whole state to be in CZ2 since, as one commission member put it, "that's where the conditions will be by the time this code comes into force."

These climate zones are based on annual Heating-Degree-Day and Cooling-Degree-Day bands, and so are used to determine what insulation levels and equipment efficiencies are cost-effective.

So if you are doing advocacy work around energy codes, you may want to suggest that they take a look at the latest climate maps even if the energy code as published has not yet.

Of course, in the spirit of "skating to where the puck is going to be", I was curious if others are using WeatherShift, Meteonorm, or other tools, and if so, how is it impacting their design?

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Mara Baum

Partner, Architecture & Sustainability

DIALOG

LEEDuser Premium Member

449 thumbs up

Sun, 04/30/2023 - 23:36

Hi Z, We’re using WeatherShift where local or client-specific data isn’t available. My understanding is that this is the least-bad option, but would definitely be interested in other insights. We also use climateatlas.ca and cal-adapt.org for projects in Canada and California respectively. I’m really pleased to see that ASHRAE has updated climate maps, which lends credibility to the adaptation issue for clients who tend towards skepticism. It’s a bit of wild west with respect to design impacts. Here are the main trends I’m seeing, whether we’re using these files or not: * Increased heat (peak and average) is the easiest to pin down quantitatively (in that data is available, and we know how to design for hotter times – not that we are going to necessarily always get it perfectly right). Passive strategies are critical, but I’m also sometimes seeing a small equipment/duct size bump for 2050 and a significant one for 2080. * Colder climates are seeing many more hours/year able to be easily served by standard air source heat pumps. (This continues to be a challenge in very cold climates, e.g. full decarb is not always a slam dunk where it’s still going to hit -40 degrees.) * In some places, live loads from wind and precipitation are becoming a more important structural design driver (vs seismic), particularly for appurtenances with risk of uplift. Unlike HDD and CDD, design wind speeds can be harder to pin down. I would love to hear how others are tackling this. * More intervention at the community, site and building scale for sea level rise / tidal surge / localized pluvial flooding. Much more wariness of building on low-lying land (finally, sheesh). * Much bigger emphasis on urban design / public realm to protect pedestrians from heat, wind, etc. I could go on, but will spare you… Mara mbaum@dialogdesign.ca From: Z Smith

Z Smith

Principal | Director of Sustainability & Building Performance

Eskew+Dumez+Ripple

LEEDuser Premium Member

4 thumbs up

Mon, 05/01/2023 - 03:16

Mara, really helpful observations. Fascinating to hear you're seeing real differences in things like duct sizes; if we think the ducts will last that long, we could oversize them for now I suppose and reap the energy savings of lower fan energy for now, or just assume that later generations would just accept higher fan energy losses with the current duct sizes.

I was fascinated to learn that SERA's newly offices in (in a renovated building in Portland) has a special high-MERV outdoor air intake filter that only gets routed to during times of wildfires, to deal with smoke. This way they don't pay the energy penalty of the super-high filter during times of good outdoor air qualitiy, but have it ready to deploy. The new normal.

Agree that the early impacts we're seeing are strangely outside the building. We were looking at a courthouse project in Greenville Mississippi where Climate Explorer on toolkit.climate.gov predicts that while the annual average daily temperature is predicted to be about 3F higher (78F vs 75F) in 2050 than today under most emission scenarios, the number of days when outdoor temperatures exceed 95F will likely double (from 37 days a year to perhaps 80). This really drives the need for more shade to render the approach to the building tolerable; as if we didn't know already, "The best time to plant a tree is 20 years ago; the next-best time is now."

As to building on low-lying land, yes, it looks like the insurance companies (private as well as Federal) are sending the signal via their flood insurance rates. Rates in New Orleans, behind the $14B of post-Katrina levees, will double, while homes in Pointe à la Hache, Louisiana, about 40 miles downriver from New Orleans, are seeing their rates rise from $694/year to $8,058/year. This will slow new construction, of course, but also has the perverse effect of trapping low-income people who own their homes there, because it renders their homes very difficult to sell. "Oh, what a world..."